Portable power impact wrench

ABSTRACT

A portable power impact wrench with a unique feature is disclosed. The wrench contains an actuator, which when activated, usually by a trigger, gives an automatic and predetermined amount of torque to the wrench. The torque is just sufficient to break the initial tightness of a nut. The wrench has utility, for example, for loosening a tire wheel lug nut which has been highly torqued by garage automatic impact wrench. The wrench also has industrial utility.

United States Patent [1 1 [111 3,912,022 Smith Oct. 14, 1975 [54] PORTABLE POWER IMPACT WRENCH 3,273,428 9/1966 Rudeke 173/937 3 67 7 l 72 l 1 [73] Assignee: Sun Oil Company of Pennsylvania,

Philadelphia, Pa. Primary Examiner-James A. Leppink Filed: y 0 1974 Attorney, Agent, or FirmGeorge L. Church; Donald R. Johnson; Anthony Potts, Jr.

57 ABSTRACT 2% 173/917; fi gg A portable power impact wrench with a unique fead 1 93 H9 ture is disclosed. The wrench contains an actuator, 1 le 0 arc 3 1 which when activated, usually by a trigger, gives an automatic and predetermined amount of torque to the wrench. The torque is just sufficient to break the ini- [56] References Cited tial tightness of a nut. The wrench has utility, for ex- UNITED STATES PATENTS ample, for loosening a tire wheel lug nut which has 2,119,968 6/1938 Shaff 173/937 been highly torqued by garage automatic impact 2,626,598 l/1953 Ta -m 173/l 19 wrench. The wrench also has industrial utility. 3,250,334 5/1966 Sussman 173/18 3,272,035 9/1966 Ekstrom et al. 173/937 10 Claims, 5 Drawing Figures Oi i 9 VIII. I

1 1 II a M J a r ma 5/ I l:2:: i= J0 Z .[l

US. Patent Oct. 14, 1975 Sheet 1 of2 3,912,022

E DIH PORTABLE POWER IMPACT WRENCH BACKGROUND OF THE INVENTION This invention relates to an apparatus or tool commonly known as an impact wrench. The latter is an electrically, pneumatically or hydraulically operated wrench that gives a rapid succession of sudden torques. Their method of operation is a rotating hammer transmiting tangentially directed impact to the working spindle, which is thereby given a jerky rotational movement. By means of a socket member fitted on to this spindle, the jerky rotational movement is transmitted to the bolt and nut which are to be tightened or loosened. A wrench is generally a hand tool that usually consists of a bar or lever with adapted or adjustable jaws, lugs, or sockets either at an end or between ends and is used 1 for holding, twisting, or turning a bolt, nut, screwhead,

pipe or other object. More particularly, this invention relates to an impact wrench that is portable and that only loosens.

Many automobile wheels are installed, rotated, and mounted on the axles by the use of power impact wrenches. The lugnuts are often so tightened that many men and women find them impossible to loosen when a tire goes flat on the road and the wheel must be changed with a hand wrench. Consequently, people can injure themselves or their car is run to a service station on the flat tire and is usually ruined.

The aforementioned problems of injury or ruining of a tire is avoided by the present invention. It is a novel, portable, impact wrench. The wrench provides a short burst of sufficient power to just break the initial tightness of the lug nut. The wrench contains an actuator which gives an automatic, predetermined amount of force while not permitting continuous use so as to unnecessarily deplete the power supply. The energy supply can be a pressure gas cartridge, the automobile battery, generator or alternator or means to operate off of the pressure in the spare tire of another car. The energy can be other well known sources.

The wrench also has industrial utility. For example, pumps in a chemical or petroleum plant are mounted to a concrete base with nuts and bolts. Because of the environment in general, corrosion often welds the nut and bolt together. Such welding also occurs to nuts and bolts on heat exchangers, control valves, etc. Under such circumstances the disclosed portable powered impact wrench would easily loosen the nut. Compressed gas, such as CO or N, as a power source would be a necessity when operating in a flammable environment.

The prior art has neither recognized the problem nor offers a solution. Thus, US. Pat. No. 3,083,598 discloses an impact tool which can be used in the tightening of large nuts. US. Pat. No. 3,093,l l4 discloses an adapted to stop the flow of pressure fluid to the tool motor upon reaching a predetermined condition in its operation. An object of the shutdown mechanism is to avoid wasting motor fluid.

SUMMARY OF THE INVENTION The portable impact wrench for loosening a nut comprises a housing; an energy source attached to the housing a rotatable bit coupled to the energy source whereby when e engaged, energy is transmitted from the source to the bit; and an actuator means associated with the bit and the energy source. When the actuator is activated, it releases a short burst of energy from the source whereby the bit, when engaged to a nut breaks the initial tightness of the nut. The housing containing the energy source, bit and actuator is of such size and weight as to be portable.

DESCRIPTION OF THE DRAWINGS The accompanying figures disclose the details of an embodiment operating off a C0 cartridge of the type used in a pellet gun.

FIG. 1 is a side view of the portable powered impact wrench.

FIG. 2 is a top view of the wrench.

FIG. 3 is a cross-section view taken along line 3-3 of FIG. 2 and further illustrating details thereof.

FIG. 4 is a perspective view of an adapter.

FIG. 5 is a rear end view of the wrench.

DESCRIPTION OF THE INVENTION One embodiment of the portable powered impact wrench is disclosed hereinafter.

FIG. 1 represents the wrench in a ready-to-operate condition. Thus, when the trigger 1 (FIG. 1) is pulled to the right, it pivots at 2. As the rear part of the trigger moves upward it raises the forward part of the CO striker release bar 3. The CO striker release bar 3 pivots at 4 and lowers the rear end out of the slot 5 in the CO striker 6. The CO striker 6 is moved forward by the spring 7, striking the protruding pin 8 of the CO release mechanism 9 (FIG. 2). The CO release mechanism 9 (FIG. 2) releases an amount of compressed CO gas from cylinder 25 (FIG. 1) in a short burst. The gas passes through the release mechanism 9 (FIG. 2), through the passage 10 (FIG. 2), into the chamber 11 (FIG. 2), there moving the wrench striker l2 swiftly forward to the position 12a, tangentially striking the loosener 13. Thus, the energy of the expanding gas is converted into a mechanical force. Release mechanism 9 is not shown in detail since it is well known to those skilled in the art.

In FIG. 2 the loosener 13 has already been positioned on the head of the automobile wheel lug 14 by properly moving it by the knurled knob 15 (FIG. 2 and 4). Repeated striking at the loosener 13, by alternately using the cocking portion 17 and the trigger 1, will loosen the wheel lug l4 enough that a standard lug wrench may be used to completely remove the lug.

The cocking portion 17 (FIG. 2) works thusly. The wrench striker 12 is in the position 12a. By hooking a finger on the extension 16 and pulling back, the wrench striker 12 is pulled back. It is held in the cocked position by the retaining ball 18 and the spring in the groove 19 in the wrench striker 12. The CO striker 6 (FIG. 1) is held cocked by the rear end of the CO striker release bar 3 (FIG. 1) at slot 5 (FIG. I). The wrench striker 12 with cocking portion 17 is returned to its starting position thus permitting the trigger 1 to start the next complete wheel lug loosening sequence.

The CO striker 6 (FIG. 1) has been returned to its starting position by a spring 20 which is compressed as the CO striker 6 moves to the position where it strikes the protruding pin 8. Thus, as shown in FIG. 1, spring 7 is compressed and spring 20 is not compressed; when the CO striker 6 hits the pin 8 then spring 7 is not compressed whereas spring 20 is. A spring 31 (FIG. 1) repositions the rear end of the release bar 3 into the slot 5.

The principle source of energy in this embodiment, compressed CO gas, is available in metal cartridges made to power CO powered pellet pistols. The cartridge 25 (FIG. 1) is inserted into the barrel 26 (FIG. 1 and by removing, then turning in, end cap 27 (FIG. 1). When the end cap 27 is turned all the way in the nose 28 (F 1G. 1) of the CO cartridge 25, is pierced by the CO release mechanism 9 (FIG. 2), readying the apparatus for use. It is preferrable that this be done when actual use is required since slow leakage may occur.

The loosener assembly starting with piece 13 (FIG. 2) is in two definite parts, one constituting the part which is struck, 13, complete with its bearing 21 (FIG. 2) and travel limiting means 22 (FIG. 1) and returning means 23, the other a knurled socket (FIG. 2, 4, and 5). The female end 24 (FIG. 4) is furnished to fit the individual wheel lug on which the tool will be used. The male end 29 or shank is the same for all. The male end 29 can fit into tool holder 21 and 21a (FIG. 3), indicating one of the eight positions that hex 24 can be positioned in too] holder 21. In this way one tool may be used for a multiple of different cars, the only additional piece needed being additional sockets 15. One housing 30 (FIG. 2 and 5) with various configurations encloses the wrench striker l2, cocking portion 17 and loosener 13 complete with bearing 21.

The energy source can be compressed gas. Nitrogen, air, and carbon dioxide are examples of suitable gas that can be compressed and stored in suitable cylinders. A small cylinder, one which can fit in the palm of ones hand is adequate. Alternatively, the energy source could be a battery or generator such as that normally used in an automobile. With such an electrical source means would be necessary to connect the wrench to the source.

The torque tightening needs of the lugs range from 60 to I ft/lbs according to several car manuals. CO cartridges, currently available, are rated at 1,500 psi at F. Calculations indicate that even at a pressure of 1,200 psi, torque of at least 200 ft/lbs is available. Lower pressures, e.g., 200 psig at 70F could be satisfactory. A suitable compressed gas source is the spare tire of another car. With industrial use, the compressed gas can be obtained from a compressor or a line containing compressed gas.

The invention claimed is:

1. Portable impact wrench for delivering a one-shot impact to loosen a nut comprising:

a. a housing;

b. an energy source associated with the hoursing;

c. a rotatable bit, rotatory impact means coupling said rotatable bit to the energy source whereby energy is transmitted from the source to the bit; and

d. actuator means associated with said impact means and said energy source comprising triggenmeans coupled with a compressed spring actuated means whereby the compressed spring activates a striker which releases a one-shot burst of energy from said energy source to said impact means to cause only a one-shot impact on said rotatable bit to break the initial tightness of the nut.

2. Wrench according to claim 1, wherein the energy source is a compressed gas.

3. Wrench according to claim 2, wherein the gas is selected from the group consisting of nitrogen, carbon dioxide, and air.

4. Wrench according to claim 2, wherein the gas is compressed in a suitable cylinder.

5. Wrench according to claim 1, wherein the housing containing the energy source, bit and actuator is of such size and weight as to be portable.

6. Wrench according to claim 5, wherein the energy source is compressed gas.

7. Wrench according to claim 6, wherein the gas is carbon dioxide.

8. Wrench according to claim 6, wherein the compressed gas is nitrogen.

9. Wrench according to claim 8, wherein the gas is compressed in a suitable cylinder.

10. Wrench according to claim 9, wherein the gas is contained at a pressure of at least 200 psig at 70F. 

1. Portable impact wrench for delivering a one-shot impact to loosen a nut comprising: a. a housing; b. an energy source associated with the hoursing; c. a rotatable bit, rotatory impact means coupling said rotatable bit to the energy source whereby energy is transmitted from the source to the bit; and d. actuator means associated with said impact means and said energy source comprising trigger means coupled with a compressed spring actuated means whereby the compressed spring activates a striker which releases a one-shot burst of energy from said energy source to said impact means to cause only a one-shot impact on said rotatable bit to break the initial tightness of the nut.
 2. Wrench according to claim 1, wherein the energy source is a compressed gas.
 3. Wrench according to claim 2, wherein the gas is selected from the group consisting of nitrogen, carbon dioxide, and air.
 4. Wrench according to claim 2, wherein the gas is compressed in a suitable cylinder.
 5. Wrench according to claim 1, wherein the housing containing the energy source, bit and actuator is of such size and weight as to be portable.
 6. Wrench according to claim 5, wherein the energy source is compressed gas.
 7. Wrench according to claim 6, wherein the gas is carbon dioxiDe.
 8. Wrench according to claim 6, wherein the compressed gas is nitrogen.
 9. Wrench according to claim 8, wherein the gas is compressed in a suitable cylinder.
 10. Wrench according to claim 9, wherein the gas is contained at a pressure of at least 200 psig at 70*F. 